Spring-wire



March 17, 1964 P. H. WINTER 3,125,392

SPRING-WIRE, DUAL-GIPPER FOR coNDucToRs;vv

Filed April 2, 1.962

vPAUL H. WINTER ATTO York

Fiied Apr. 2, 1962, Ser. No. 184,671 7 Claims. (Cl. 339-95) Thisinvention relates to electric wiring devices and more particularly to aspring-wire, dual-gripper for conductors.

It is a general object of the present invention to provide a novel andimproved gripper for two conductors formed from a single length ofspring-wire arranged for cooperation with a stationary terminal plate.

An important object of the invention resides in the arrangement andcooperation of a dual-gripper of spring wire with a terminal plate whichholds the former in position in a formed recess in a moulded insulationpart without the need for any additional fastening or cover means.

Another important object of the invention consists in the provision ofaccess directly to the gripper springs individually by a common tool toalone release either conductor gripped thereby.

An important feature of the invention consists in holding the dualspring in position by having the bottom of the terminal plate engage andhold its transverse central portion against outward movement.

Other and further objects and features of the invention will be moreapparent to those skilled in the art after a consideration of thefollowing specicationfand the-accompanying drawing, wherein is discloseda single examplary embodiment of the invention, with the understandingthat such changes and modifications may be made therein as fall withinthe scope of the appended claims without departing from the spirit ofthe invention.

In said drawing:

FIGURE l is a bottom plan View of a porcelain lightingxture equippediwth two spring-wire, dual-grippers constructed in accordance with thepresent invention;

FIGURE 2 is a fragmentary longitudinal section, on a larger scale takentherethrough-on line 2-2 of FiG- URE l;

FIGURE 3 is a perspective View, on the larger scale, of the spring-wire,dual-gripper and its cooperating terminal plate removed from theinsulating ixture base;

FIGURE 4 is a view similar to FIGURE 2, but illustrating a conductor inposition held by one part of the gripper, and with the terminal plateshown in longitudinal section between the wings thereon;

FIGURE 5 is a view similar to FIGURE 4,.but showing the gripper tiexedby a tool to release the vconductor for withdrawal; and

FIGURE 6 is a fragmentary View, like FIGURE l, on an enlarged scale,showing in dot and dash lines one complete gripper assembly in positionin a recess in a mouded insulation base.

The invention is illustrated for convenience in connection with amoulded, box-mounting type of lamp holder, commonly referred to as aboxcover socket or porcelain light fixtureV for bathroom, kitchen andsimilar uses, but obviously this is merely by way of illustration forthe terminal device is capable of use in many other positions Wheresufiicient housing depth, in moulded insulated material, is available toaccommodate it.

Referring now to the drawing and tirst to FIGURES 1 and 2, it will beseen that the wiring device comprises a moulded base or housing 10,suitably perforated at 11- 11 for the reception of mounting or fasteningscrews which secure it to act as a cover for a junction or rixture boxof the circular or octagonal type. The fragmentary United States PatentO thetic resin.

3,125,392 Patented Mar. -17, 1964 ICC section of FIGURE 2 illustratesthe socket sleeve 12 projecting integrally and centrally from the frontface, of the circular base shown in FIGURE l, and formed of `suitableinsulating material such as porcelain or syn- A conventional metal screwshell 13 is mounted in the central recess thereof, and secured inIposition by means of a rivet 14, and is illustrative of one of twocontacts each of which is accommodated by a dual-gripper for-conductors,formed-in accordance with lthe principal part of the present invention.

The back wall V15 of the wiring device is substantially fiat, as shownto iit against a wall surface, and is provided with various lighteningpockets 16 and with two recesses 18 spaced somewhat less than 180 apartto accommodate the wire grippers for conductors supplying current to thedual `wire gripper.

The dual wire grippers and their essential equipment, arranged in therecesses 18, are identical in construction and the` description of onewill su'ice for both. As seen in FIGURE l` a terminal plate 2t) isprovided against the inner wall of the recess 18, and comprises, as seeninthe `other figures, a flat plate 21 having side wings 22 parallel toeach other and bent up substantially at right angles to the flatsurfaces of the plate 21. A tang 23 is bent at right yangles from theupper edge of the plate, is somewhat narrower than the rest of theplateand is perforated as at A24 to accommodate a rivet such as 14 shownheaded over in FiGURE 2 whereby the terminal plate is placed in elec-Vtrical communication with the socket contact 13. The Vother wiregripping device has its tang connected to a central contact, not shown,for the socket. The tang 23 is accommodated in a shallow recess 25 inthe back wall t ofthe wiring device, thus keeping all parts below theliat surface thereof.

The recess 18 is of a complex shape as best seen in FIGURE 6 consideredalong with FIGURE 2. Therecess lincludes a pair of parallel grooves 26normal to 1 the face of the plate 2l and having their outer walls 27substantially continuations of the inner faces of the wings 122. Theplate 2l is accommodated in a transverse channel v23'which connectstogether the notches or grooves 26. The minimum dimension of the channel28, i.e., measured in the direction of length of the notches 26 Lis onlyslightly greater than the thickness of the plate 21 to readilyaccommodate it but to leave between it and .the face of the abutment 29between the notches 26, a space 29 less than the thickness of the plateand certainly less thanthe diameter of the gripping wire which will belater described.

The notches 26, as best seen in FIGURES 2 and 4, open out through theback wall of the wiring device, having substantially parallel side wallsand an irregular bottom wall composed of the wall 39 almost normal tothe flat surface of the back of the wiring device, the wall 31 extendingat an angle of approximately 45 to the axis through the socket of thewiring device, and a bottom Wall 32 normal to said axis. A portion 33slightly elevated above this bottom wall 32 lies only beneath the loweredge of plate 21, which it will be appreciated is held in position bythe tang 23 and the rivet 14. Behind the plate 21 the rear wall of thechannel may be inclined to provide draft for the process of molding thedevice, and, this is true of the other walls which are more nearlynormal to the surface of the back of the wiring device.

As seen in FIGURES l and 6 the transverse channel 2S extends laterallybeyond each of the notches Z6 and is Zia thickened at and beyond thenotches, as seen at 35, to accommodate the wings 22 as best seen inFIGURE 6. At the junctions of these wings with the plate 21 arepreferably formed shallow grooves 36 in alignment with the longitudinalcenters of the notches 26 to assist in guiding the conductors, to beheld by the grippers, and to give them a somewhat greater Contact areawith the terminal plates as well as to prevent them from rollinglaterally. Such conductors are indicated in section at 37 in FIG- URE 6and for the purpose of permitting them to be inserted longitudinally, asindicated in FIGURE 4, the upper edge of plate 21 and its appurtenancesare exposed through the back of the wiring device.

The dual gripper for the conductors is best seen in FIGURE 3 where it isgenerally referred to by the reference character 40. It is a complexformation of resilient steel wire, such as piano wire, bent from onepiece thereof into the structure illustrated at 4t) to provide a pair ofgrippers. Each gripper has a free end cooperating with the wall ofterminal plate 20, just within one of the wings thereof, serving to gripa wire which is introduced through the open side of notch 26 so as toprevent it from being withdrawn in accordance with the illustration inFIG- URE 4.

For purposes of convenience, the wire component 40 may be looked on astwo, parallel-positioned, wire grippers each composed of two arms 41 and42 connected together by an elbow 43 and divergent as best indicated inFIGURE 2. The arm 41, referred to as the gripper arm, is straight fromits junction with the elbow, and the arm 42 is straight for most of itslength beyond the elbow and then has a short section 44 bent through anangle of about in order that its end may rest on the shelf 33,previously referred to, when it is parallel to the bottom wall 32 of thenotch in which it is received. To integrate the two wire gripper springsjust delined, the wire beyond the parts 44 is bent at right angles andintegrated with a transverse connection portion 45.

This whole component is shaped and sized to be received with each wiregripper in one of the two notches 26 and with the connecting portion 45in channel 28, prior to the introduction and securing of the terminalplate 20. It is positioned as illustrated in FIGURES 2, 4 and 5 byhaving the elbows 43 resting against the walls 30 near the upper edgesof the notches and by having the cross connecting portion 45 rest on theshelf 33 which places it beneath the lower edge of plate 21 as seen inFIGURE 4, when the latter is finally positioned, which serves to holdthe wire complex 4t) in the position illustrated in that figure with theends 41 of the gripper arms 41 engaging against or substantially againstthe plate 21 at a distance below the level of the elbow, which reachesalmost two the rear surface of the wiring device base.

This makes each wire 41 form an acute angle with the surface of theplate, which angle decreases in extent as the conductor wire 37 isforced between its end 41 and the groove in the conductor plate as seenin FIGURE 4. The action of forcing such wire in position is resisted bythe engagement of the bend 43 in the gripper wire with the surface 30causing the wire to iiex in the bend and strongly forcing the sharp endthereof against the conductor wire, which is of soft copper, at such anangle that it cannot be withdrawn. Any tendency to withdraw it and thegripper wire along with it is resisted by the plate 21 resting on thestretch 45 connecting the two sets of gripper wires. This stretch cannotmove out from beneath the lower edge of the plate 21 since the barrier29 is too close against the outer face of plate 21 to permit movement ofthis portion upwardly. To assist in maintaining the gripper ends 4l ofthe gripper wires in alignment with the introduced conductors as seen at37 in FIG- URE 6, the walls of each of the notches 26 are spaced onlysuihciently far apart to loosely receive the wire of the gripper but toprevent it from having any substantial lateral movement. FIGURE 6 showsthat the conductor 37 is also limited in its lateral movement by firstthe inner wall of the adjacent wing 22 on the plate 21 and by the wall47 which is offset slightly inwardly from the inner wall of the notch26. Thus, the conductor 37 is hemmed in on three sides by stationarywalls, one having groove 36 therein, and engaged on the fourth side bythe end 4l. of the gripper arm 41 in such a manner that no matter howhard the conductor may be pulled it is only gripped tighter.

In order that the wireman may Withdraw a conductor should he introduceone improperly or place the wrong one in gripping engagement, a recess50 seen in FiG- URES 1 and 6, and perhaps best in FIGURE 5, extends intothe material of the base and through the outer wall of notch 26 andpermits the introduction of a tool, such as a screwdriver as seen at 51in FGURE 5, to engage the upper side of portion 41 of the gripper anddepress it as indicated by the arrow in FIGURE 5 whereby its end 4.5 isWithdrawn from its engagement with conductor 37 so that the latter canreadily be withdrawn and the proper conductor substituted.

The arrangement just described makes a simple, low cost and veryeffective wire gripper requiring a minimum of parts and of assemblyoperation. The materials are cheap and simple to manufacture, and theamount of time saved by the wiremen is very considerable over that ofusing screw-type terminals.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. An automatic dual conductor wire gripper comprising an insulatingbase, dual, parallel, laterally spaced substantially V-shaped notches insaid base terminating substantially at a surface thereof and having oneleg of each V-shaped notch substantially normal to said surface, atransverse channel connecting said legs for substantially their fulldepth and extending laterally beyond them, a terminal plate secured inand nearly lling said channel having a Wing on each edge substantiallyat right angles to the plate and each directed generaly toward the otherleg of each V, a conductor wire gripper comprising a pair of divergentarms of spring wire integrated by a bend of the order of and arrangedone pair in each said notch with the free end of each outermost armsubstantially engaging said plate adjacent one of said wings at aposition deeper in its notch than the bend between the arms of the pair,a straight transverse integral portion of said spring wire connectingthe inner ends of the other arms together, and extending in said channelbeneath the lower edge of said terminal plate, whereby the dual springwire gripper unit is maintained in position in the V-shaped notches andconnecting channel.

2. The wire gripper of claim 1 in which said terminal plate is groovedadjacent each wing to guide the free ends of said outermost arms andalso the inserted conductor wire.

3. The Wire gripper of claim 1 in which the wall of said transversechannel which faces said terminal plate is spaced therefrom less thanthe diameter of said spring wire and said terminal plate substantiallyholds the transverse integral portion of said gripper assembly againstthe bottom of said channel.

4. The wire gripper of claim l in which the said base laterally of andthrough one side wall of each V-notch is recessed close to the saidtransverse channel and to a depth below the position of the outermostarm of gripper wire therein whereby a tool may be inserted to depresssaid arm and release a wire gripped thereby.

5. The wire gripper of claim 4 in which the recessed side wall of eachV-notch is the outermost one.

6. In a wiring device housing of insulating material containing at leastone contact member and means for automatically gripping and connecting apair of conductor wires to said contact comprising a terminal plateelectrically connected to said contact and having parallel wings turnedup from opposite edges thereof, one end of said plate and of the wingsbeing exposed through a wall of said housing to slidably receive an endsection of one of said conductor wires adjacent each wing, a narrowgroove in said housing extending normal to said plate adjacent the innerwall of each wing, a conductor wire gripping means in each groovecomprising two arms of spring wire having an integral connecting elbowand diverging therefrom at a small included angle, a transverse channelconnecting said grooves and receiving said terminal plate, one of thearms of each gripping means being the gripping arm and having a free endsubstantially engaging said terminal plate adjacent a wing thereof andmore remote from the said surface end of the plate than said elbow, theends of the other arms of each gripping means being integrated by atransverse portion of wire located in the bottom of said transversechannel and beneath the lower edge of said terminal plate for retentionin the channel thereby, a wall in each groove being References Cited inthe tile of this patent UNITED STATES PATENTS 2,883,641 Despard Apr. 21,1959 3,018,461 Smith Jan. 23, 1962 FOREIGN PATENTS 751,675 Great BritainJuly 4, 1956

1. AN AUTOMATIC DUAL CONDUCTOR WIRE GRIPPER COMPRISING AN INSULATINGBASE, DUAL, PARALLEL, LATERALLY SPACED SUBSTANTIALLY V-SHAPED NOTCHES INSAID BASE TERMINATING SUBSTANTIALLY AT A SURFACE THEREOF AND HAVING ONELEG OF EACH V-SHAPED NOTCH SUBSTANTIALLY NORMAL TO SAID SURFACE, ATRANSVERSE CHANNEL CONNECTING SAID LEGS FOR SUBSTANTIALLY THEIR FULLDEPTH AND EXTENDING LATERALLY BEYOND THEM, A TERMINAL PLATE SECURED INAND NEARLY FILLING SAID CHANNEL HAVING A WING ON EACH EDGE SUBSTANTIALLYAT RIGHT ANGLES TO THE PLATE AND EACH DIRECTED GENERALY TOWARD THE OTHERLEG OF EACH V, A CONDUCTOR WIRE GRIPPER COMPRISING A PAIR OF DIVERGENTARMS OF SPRING WIRE INTEGRATED BY A BEND OF THE ORDER OF 180* ANDARRANGED ONE PAIR IN EACH SAID NOTCH WITH THE FREE END OF EACH OUTERMOSTARM SUBSTANTIALLY ENGAGING SAID PLATE ADJACENT ONE OF SAID WINGS AT APOSITION DEEPER IN ITS NOTCH THAN THE BEND BETWEEN THE ARMS OF THE PAIR,A STRAIGHT TRANSVERSE INTEGRAL PORTION OF SAID SPRING WIRE CONNECTINGTHE INNER ENDS OF THE OTHER ARMS TOGETHER, AND EXTENDING IN SAID CHANNELBENEATH THE LOWER EDGE OF SAID TERMINAL PLATE, WHEREBY THE DUAL SPRINGWIRE GRIPPER UNIT IS MAINTAINED IN POSITION IN THE V-SHAPED NOTCHES ANDCONNECTING CHANNEL.